Quick install

Compiling OPAM

$ ./configure
# (or ./configure --prefix=$HOME if you want to install under your $HOME)
$ make

This will fetch the archives if they are not already downloaded and then build
OPAM. If you just want to get the necessary dependencies without compiling the
project, run make clone.

Installing OPAM

To install opam simply run:

$ make install

or

$ sudo make install

if you need root privileges.

This way, OPAM binaries will be installed in $prefix/bin, where
prefix can been specified during the ./configure phase.

Using opam

All of the OPAM state is held in the ~\.opam directory in your home
directory, including compiler installations. You should never need to switch to
a root user to install packages. Package listings are obtained through remote
sources.

$ opam init
$ eval `opam config env`

The first command creates ~\.opam and sets up opam.ocamlpro.com as the
default repository. The second command updates your local environment to use
the packages installed by OPAM. You should add the eval line to your
~/.profile so you don't forget to run it before using OCaml.

$ opam list

As expected, this command lists all the available packages. We can now install
some packages (for instance lwt):

$ opam install lwt

OPAM is able to track optional dependencies. This mean that installing an
optional dependency of a package will recompile the package and all its
forward dependencies. For instance:

$ opam install react

will install react and also recompile lwt with the right ./configure
options to support react, and also all the packages which further depend on
lwt.

Installing on other OCaml compiler

OPAM also manages meta-data about OCaml compilers. So in order to install a new
version of the compiler, you can run:

$ opam switch 4.00.1
$ eval `opam config env`

The first command will download and install ocaml-4.00.1, and the second
command will update the environment variables. You can then install packages --
they will be installed on a different under ~/.opam/4.00.1.

In order to return to the system-wide OCaml installation, simply run:

$ opam switch system
$ eval `opam config env`

You can use opam switch list to display the list of available compilers.

Version pinning

$ opam pin <package> </local/path>

This command will use the content of </local/path> to compile <package>.
This means that the next time you will do opam install <package>, the
compilation process will be using a mirror of </local/path> instead of
downloading the archive. This also means that any modification to
</local/path> will be picked up by opam update, and thus opam upgrade
will recompile <package> (and its forward dependencies) if needed.

To unpin a package, simply run:

$ opam pin <package> none

You can also pin a package to a specific version: opam pin <package> <version>
or to a git repository: opam pin <package> </remote/path/to/git> or
opam pin <package> </local/path/to/git> -k git.

Repositories

OPAM supports multiple package repositories, for example for development
packages.

$ opam remote list

Uninstall

To uninstall OPAM, use:

$ make uninstall

Auto-completion

shell/ contains shell-scripts to add auto-completion to OPAM. The script is not
installed by default, so to activate the mode you can either:

move it at the right location (depending on your OS, for instance
/etc/auto-complete.d/opam on Debian)

copy it somewhere in you path and source it in your .profile.

Documentation

The main documentation entry point to OPAM is the user manual, available using opam --help. To see the
help for a specific command, use opam <command> --help.